This paper proposes a reduction method for DC-link ripple current and common-mode voltage (CMV) in a hybrid active neutral-point-clamped (ANPC) inverter. A Si and SiC hybrid ANPC inverter has been developed recently to overcome the extremely high cost of a full-SiC ANPC inverter. A hybrid ANPC requires much fewer SiC MOSFETs than a full-SiC ANPC inverter while providing a comparable power density. Voltage source inverters such as hybrid ANPC inverters utilize electrolytic capacitors, which have a large capacitance per volume, as a DC link. However, an electrolytic capacitor is one of the most vulnerable components in a power electronic converter due to its small allowable ripple current. A large ripple current flowing into the electrolytic capacitor generates a heat loss, which shortens the lifetime of the capacitor. Furthermore, the common-mode voltage (CMV) causes an undesirable leakage current and electromagnetic interference. The CMV depends on the pulse-width modulation of the voltage source inverters. The proposed method enhances the reliability of the hybrid ANPC inverter by reducing the DC-link ripple current and CMV simultaneously. The effectiveness and validity of the proposed method are verified through simulations and experimental results.
This work was supported in part by the Korea Electric Power Corporation under Grant R19XO01-20, and in part by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry, and Energy (MOTIE) of the Republic of Korea under Grant 20206910100160.
